DE632444C - Process for the preparation of disazo dyes - Google Patents

Description

Process for the production of. Disazo dyes It was found that by combining optionally substituted Diazoben7.olsulfonsäuren with an i-amino-2, 5-dialkoxybenzene in acidic solution, further diazotization of the aminoazo compound and coupling with an o-oxybenzenecarboxylic acid can produce mordant dyes.

The dyes obtainable by the present process: are suitable especially for cotton printing. With chrome stain they give red-brown to purple-brown, previously unavailable. Shades of good fastness properties and thus fill: a gap in the range of chrome colors for cotton printing the end.

In front of the dyes known from patent 54544o and obtained by coupling a diazotized aminoazo compound obtained from components of the naphthalene series with an o-oxycarboxylic acid, the new dyes, as well as those known from patent 22162o, contain only one alkoxy group in the middle component to red-orange coloring by dyeing in strong and deep brown tones. Example i 2o, 75 parts of i-amino-4-chlorobenzene-3-sulfonic acid are dissolved in a solution of 5.5 parts of sodium carbonate in i 50 parts of water. A concentrated solution of 6.9 parts of sodium nitrite is then added. This solution is allowed to flow gradually onto a mixture of 45 parts of hydrochloric acid and 50 parts of ice, with stirring. The temperature of the reaction mixture - is kept at 0 to 10 ° C.

The diazo suspension thus obtained - free of excess nitrous acid - is allowed in a prepared solution of 1 5.3 parts of i-amino-2, 5-dimethoxybenzene in i 5o parts of water, hydrochloric acid .enthält so much that the solution just except congo is to flow in. The mixture is stirred well and the temperature is gradually increased from an initial 10 ° C to 20-25 ° C. After about i 5 hours of stirring, the coupling is complete. The resulting red-brown aminoazo compound is then largely excreted as a poorly soluble body. A further 30 parts of hydrochloric acid are added. The temperature is increased to 60 ° C. and, with thorough stirring, a concentrated solution of 6.9 parts (-E- slight excess) of sodium nitrite is allowed to flow in slowly. When the nitrite is no longer consumed, stirring is continued for a short time. The mixture is then allowed to cool, the yellow-brown diazoazo compound which has precipitated out is filtered off and it is stirred in a moist state into a cooled solution of 13.8 parts of salicylic acid, 5 parts of solid sodium hydroxide and 20 parts of sodium carbonate. The coupling takes place immediately. It is stirred for a few more hours, then heated to 40 ° C. and cooled. The disazo dye obtained is precipitated by acidification with hydrochloric acid, filtered off and converted into the potassium salt in the usual way.

The new dye represents a brown powder that turns-in hot Water @eic: t 'dissolves with an orange-brown color. When this solution is cold, it crystallizes most of the coloring matter is off. The solution color in: .koi "centered sulfuric acid is red-purple. In cotton print with chrome stain, the dye produces deep red-brown Tones with good fastness properties.

In this example, the i-amino-4.-chlorobenzene-3-sulfonic acid can be used with a similar result the corresponding amount of i-aminobenzene-sulfonic acid or i-aminobenzene-3-sulfonic acid and 'instead of i-amino-2, 5-dimethoxybenzene, i-amino-2, 5-diethoxybenzene is used Will. Example-2 21.8 parts of i-amino-q.-nitrobenzene-3-sulfonic acid are dissolved in aqueous solution Dissolved sodium carbonate solution and diazotized in the usual way. The suspension of the Diazo compound is left in a solution of 15.3 parts of i-amino-2,5-dimethoxybenzene in 15o parts of water, prepared with the addition of as much hydrochloric acid as the congosauren Reaction is required to flow into it. The reaction mass is stirred at 25 ° C; until coupling is complete (approximately 15 hours). The aminoazo compound thus obtained is then for the most part - eliminated. There are another 30 parts of hydrochloric acid added, and at 6 to 70 ° C with thorough stirring by slowly adding Sodium nitrite solution (6.9 parts + small excess) diazotized. The resulting poorly soluble diazo compound is filtered off and in a moist state in a , cooled solution of 13.8 parts of acylic acid; , a solution; made of - 5 parts; h'ätriumhydroxyd, 20 parts of sodium carbonate and 25o parts of water, stirred in. The coupling ends after a short time. The work-up is carried out in a similar way Way as described in example i.

The potassium salt of the new disazo dye is a dark brown powder, which in hot water easily turns red-brown in color, in concentrated sulfuric acid dissolves with blue-violet paint.

In chrome printing on cotton, the dye produces purple-tinged browns Shades of good fastness properties.

Instead of the i-amino-q.-nitrobenzene-3-sulforic acid, the isomers Amines, e.g. B. i - amino - 3 - nitrobenzene - q. - sulfonic acid or i-amino-2-nitrobenzene-q.-sulfonic acid, and instead of salicylic acid its homologues, -z. B. 6-methyl-i-oxybenzene-2-carboxylic acid or 5-methyl-i-oxybenzene-2-carboxylic acid can be used. It will then be similar Get dyes:

Claims (1)

PATENT CLAIM: Process for the preparation of disazo dyes, characterized in that diazotized, optionally substituted aminoazo dyes from diazobenzenesulfoxy acids and z-amino-2,5-dialkoxybenzenes are coupled with o-oxycarboxylic acids of the benzene series.